The present invention relates to a process for preparing modified epoxy resins particularly useful in outdoor coatings.
U.S. Pat. No. 3,763,097 describes a polyether resin which is prepared by heating, under acidic conditions, a reaction mixture of 0.5 to 8 equivalents of a cyclic 1,2-diepoxide with one equivalent of tris(2-hydroxyethyl)isocyanurate. The preferred epoxy resins are those in which the diepoxide is cycloaliphatic (including examples such as vinyl-cyclohexene dioxide, dicyclopentadiene dioxide, alicyclic diepoxy adipate, and alicyclic diepoxy carboxylate) or aromatic (including the diglycidyl ethers of aromatic bisphenols). Such epoxy resins are useful in making powder coatings, enamels and insulating varnishes.
There remains a need, however, for epoxy resins having a combination of flexibility and outdoor stability.